超極厚 H 形鋼, 柱はり接合部の剥離破壊に関する実験的研究

抄録

The behavior of super heavy H-shape on pull-out type brittle fracture at beam-to-column connection has been studied, and a method against such fracture is proposed. The conclusions obtained are as follows; (1) Pull-out type fracture occurs only when beam-flange has thickness over 40mm, leading to the lack of ductility required for aseismic design. (2) A slow crack propagates from an original crack between beam edge and end tab, and a starting point of the fracture is bead end. Therefore, the crack is considered to be the initiation of the fracture. (3) At the welded zone of T-joint, super heavy H-shape has the weakest part between heat-affected zone and base metal. Theoretically, the crack under 10mm in length can cause such fracture at this part. (4) Strain concentrates on beam edge because of plastic constraint from column, and equivalent plastic strain of this part can be adopted as a judging parameter of fracture type. (5) Even in the case the beam-flange thickness is over 40mm, pull-out type fracture can be prevented by the end tab cutting or the use of proposed "tab-plate".